1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
lord [1]
3 years ago
12

How do we know there is Dark Matter in other galaxies? a. it occasionally lum inesces b. flat rotation curves in spiral galaxies

c. matter rotates slower the farther from the center of a spiral galaxy d. it blocks our view in elliptical galaxies
Geography
1 answer:
lesantik [10]3 years ago
8 0

Answer:

b. flat rotation curves in spiral galaxies

Explanation:

Dark matter accounts for majority of the matter in the universe (about 85%). It is considered to be composed of subatomic particles which are yet to be discovered. Dark matter cannot be observed because it does not emit light that can be detected. Only its gravitational effect is visible.

Astronomers when calculated the mass of the visible matter and tried to account for the observed speed of stars in the galaxy, there was a mismatch. To understand what caused this mismatch, astronomers gave name to the invisible matter as the Dark Matter.  

The expected velocity of stars should decrease away from the near the center of the galaxy but a constant velocity of stars was observed that is a relatively flat rotation curve was obtained.  

Thus, flat rotation curves in spiral galaxies in an evidence of Dark Matter.

You might be interested in
Identify the statement that is true about the abyssal plains. a. The abyssal plains of the eastern Atlantic Ocean stretch from t
Tatiana [17]

Answer:

The abyssal plains of the eastern Atlantic Ocean stretch from the continental shelf to the base of the mid-ocean ridge.

Explanation:

The others are false

5 0
3 years ago
When people move from rural to urban areas, where do they settle first? What are some common issues with these types of settleme
Oksanka [162]

Answer:

Due to the adverse conditions of poverty and unemployment in the rural areas, people migrate to urban areas. In urban areas they find increased employment opportunities and better living conditions.

Explanation:

answer above

4 0
3 years ago
If x^2-kx+9=0 has equal roots,find the positive value of k
Fantom [35]

Answer:

k =x + 9/x

Explanation:: Idk hopefully this helps if not im sorry :/

6 0
4 years ago
The human desire to control an area or people is called __________.
soldi70 [24.7K]
<span>The desire of human to take control of a specific area or certain group of people is called the territoriality. This is associated with how spaces should be used, its ownership, and occupancy, and possessions. This is also associated with the wanting to lead the group of people living in a certain populace. </span>
8 0
3 years ago
Read 2 more answers
Pls help, this is Geogrophy btw.
larisa [96]

Answer:

d

Explanation:

they were use to fighting on foot that have nice weapons they don't have armor and they not talking

7 0
3 years ago
Read 2 more answers
Other questions:
  • Ñacunday National Park is known for which feature? (1 point)
    7·2 answers
  • In what climate region can most of Canada's forest area be found
    12·2 answers
  • Can a nonfoliated igneous rock undergo metamorphism and be turned into a foliated igneous rock? yes no
    13·1 answer
  • Why do earthquakes frequently occur between the valleys running between Mid-Ocean ridges? HELP
    10·1 answer
  • How are earthquakes, tsunamis, and tectonic plate movements alike?
    14·1 answer
  • List and describe the pieces of evidence for seafloor spreading
    15·1 answer
  • The tilt of the earth on its axis
    7·1 answer
  • Which statement about local and global winds is true?
    13·2 answers
  • What is the effect of variations in the number of sunspots?
    14·1 answer
  • After Christopher Columbus arrived in the Caribbean in 1492, Europeans established colonies in the Americas and trade routes acr
    12·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!